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A233253
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Number of n X 5 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs).
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1
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36, 13952, 6049792, 2647261184, 1159192379392, 507618560835584, 222290692443996160, 97343107609552486400, 42627429627049642295296, 18666938062087506825838592, 8174421486934238668125110272
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 512*a(n-1) - 33792*a(n-2) + 589824*a(n-3).
Empirical g.f.: 4*x*(9 - 1120*x + 30720*x^2) / ((1 - 32*x)*(1 - 480*x + 18432*x^2)). - Colin Barker, Oct 11 2018
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EXAMPLE
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Some solutions for n=2:
..0..1..2..4..3....0..1..2..5..3....0..1..2..1..0....0..1..2..4..2
..5..4..3..5..2....2..1..2..0..1....2..1..0..3..0....2..4..0..1..5
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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